Zusammenfassung der Ressource
Biology F211 Cells
Part 2
- Biological membranes - fluid boundaries
- Roles of membranes
- Separating cell contents from the outside environment
- Separating cell components from the cell cyoplasm
- Cell recognition and signalling
- Holding the components of some metabolic pathways in place
- Regulating the transport of materials into or out of cells
- A phospholipid molecule has a hydrophillic head and a hydrophobic tail
- These properties come from the
way charges are distributed
across the molecule
- If phospholipid molecules are completely
surrounded by water, a bilayer can form
- The basic structural component of all biological membranes
- Specialisation of cell surface membranes
- Plasma membranes of the cells in a growing shoot contain receptors that allow
them to detect the molecules that regulate growth
- Muscle cell membranes contain a large number of channels that allow rapid
uptake of glucose to provide energy for muscle contraction
- The internal membranes of chloroplasts contain chlorophyll and other
molecules needed for photosynthesis
- The plasma membranes of white blood
cells contain special proteins that enable
the cell to recognise foreign cells and
particles
- All membranes are permeable to water molecules
because water molecules can diffuse through the bilayer
- The fluid mosaic model
- Communication and cell signalling
- Crossing membranes 1 - passive processes
- Crossing membranes 2 - active processes
- Water is a special case